Severe weather environments in long term regional climate simulations for North America

James Correia Jr., PNNL, Richland, WA ; and R. Leung

The global mean surface temperature has increased by 0.75 C since the pre-industrial era, and climate is projected to continue warming in the coming decades due to build up of greenhouse gases. Associated with the warming is an increase in atmospheric water vapor and potential changes in severe weather. The North American Regional Climate Change Assessment Program (NARCCAP) is developing multiple regional climate change scenarios for North America using an ensemble of global and regional climate models. Regional climate models, with a grid spacing greater than 10 km and using parameterized convection, cannot fully account for the differing convective modes or environmental details that accompany them. However, regional models may be able to simulate some of the larger scale features that lead to convection and severe weather. This study aims to document the warm-season model climatology of severe weather parameters, as well as dynamical processes which lead to severe weather as simulated by the WRF regional climate model. The simulations, driven by global reanalysis and a current and future global climate simulation will be compared to observations of the current climate (1979-2003) over the NARCCAP domain. This validation will provide useful insights on the ability of the model to simulate severe weather environments and potential future changes. Recorded presentation